The present invention relates to an exercise device. More particularly, the present invention relates to a portable exercise device which employs elastic resistance to strengthen muscles.
Tensile exercising devices have been developed which can be stretched, pulled or extended by an exerciser in order to develop and maintain body muscle. Tensile exercise devices in the prior art included a series of tightly coiled springs having handles attached at opposite ends. As the handles are pulled apart, the springs are extended and provide resistance. The resistance is overcome by the person using the device which results in an increase in muscle mass within the body.
While the coiled springs are useful as tensile exercising devices, the coiled springs present several drawbacks including, but not limited to weight, size and appearance. Additionally, the extended springs have the potential of pinching the skin of the exerciser when the spring is contracted. Besides, creating the potential of pinching the skin of the exerciser, the springs are uncomfortable when pressed against the exerciser's skin.
In addition to creating a safety issue, the handles connected to the springs are typically made of a relatively rigid material. The rigid handles are needed to properly interface with the coiled springs and other mechanical elements of the device. The rigid handles become difficult to grip due to perspiration and may slip out of the exerciser's grip. If the exerciser loses the grip on the handles while the springs are extended, the springs will recoil uncontrollably and potentially injure the exerciser or bystanders or cause damage to the device or nearby property.
Other tensile exercising devices employ rubber or other elastic materials which have handles fastened at opposite ends. While devices which employ rubber or other elastic materials are generally more portable than coiled spring devices, the handles are still typically made of a rigid material in order to facilitate attachment of the handles to the rubber or elastic materials. Using a rigid material for the handle results in the same problems as discussed regarding the handles attached to the coiled springs, namely, difficulty in gripping the handles while the exerciser is perspiring.
Alternatively, the handles can be integrally formed with the rubber or elastic material. While the handle is made of a non-rigid material, facilitating better gripping, there are drawbacks to the integral handle design, namely, when the handle fails or develops a defect, the entire device must be replaced. An alternative to the integral handle is to use loops of material for gripping. However, loops of material tend to be uncomfortable to the exerciser, and do not allow the exerciser to exercise the muscles in the lower arms, hands and fingers.
Another common problem with prior art tensile exercise devices is that the resistance can not be varied. Because the resistance can not be varied, beginners would have difficulty in using the device while people who have well developed muscles would not have enough resistance to maximize the benefits of the device. Additionally, the length of the tensile exercise devices typically cannot be adjusted to accommodate different sized people. When the device does not fit the exerciser properly, the exerciser cannot efficiently utilize the device and therefore achieves less gains than if the device properly fit the exerciser.